Vapor fueled engine

ABSTRACT

A fuel supply assembly providing vaporized fuel to an engine wherein a quantity of liquid gasoline fuel is controllably heated for a desired vapor emission from the liquid fuel, and a conduit arrangement conducts the vapor, intermixes it with ambient air and conveys the intermixture to the engine&#39;s combustion chamber. A sensor in the engine exhaust monitors the hydrocarbon content of the exhaust and control valving controls the vapor to air intermixture in response to the monitor for maintaining a desired intermixture that produces the desired hydrocarbon content.

RELATED APPLICATION

This is a continuation-in-part of co-pending U.S. patent applicationSer. No. 10/706,507 entitled “Vapor Fueled Engine” filed on Nov. 11,2003, and claims priority to said '507 application.

FIELD OF THE INVENTION

This invention relates to the use of vaporized fuel to power an engineand, more particularly, to improvements that enhance fuel efficiency.

BACKGROUND OF INVENTION

It is known that under some conditions the use of vaporized fuel versusliquid fuel for gasoline powered vehicles can reduce the emission ofhydrocarbons conveyed into the atmosphere, while also increasing fuelefficiency. The problem that has lingered is how to obtain and retainthose benefits over the changing conditions in which such vehicles aretypically driven.

SUMMARY OF THE INVENTION

As known and as described in the commonly owned U.S. patent applicationSer. No. 10/002,351, now U.S. Pat. No. 6,681,749, (incorporated hereinby reference), fuel efficiency can be improved by heating a quantity ofgasoline to cause vaporization, directing the vapor into a stream ofambient air, establishing a desired air-to-fuel mixture and directingthe mixture into the intake manifold of an engine.

Whereas the system as disclosed in the above application has resulted insignificant improvement, it has not achieved the consistency ofoperation desired.

It is known that there is an optimum fuel-to-air mixture that needs tobe maintained. A fuel-to-air mixture of 1 to 20 is likely too richresulting in an unacceptable percentage of hydrocarbons in the fuel thatare not properly combusted and fuel efficiency is reduced. A 1 to 40mixture is too lean with today's catalytic converters (CATs) andproduces an emission of nitrogen oxide that is prohibited by the EPAemission standards. A fuel-to-air mixture of about 1 to 30 is aboutoptimal for current gasoline engines used in vehicles and an objectiveof the invention is to control the fuel-to-air mixture to maintain theratio in the range substantially at, e.g., 1 to 30.

Consistent with the above objective, the mixture is monitored andadjusted throughout operation of the engine. This is accomplishedautomatically by the use of valves that control the flow of vapor fueland/or ambient air that is mixed prior to entry of the vapor fuel intothe engine's intake manifold. The valves are coupled to a control thatis in turn coupled to a vehicle's 02 sensor which senses 02 emissions ina vehicle's exhaust (a standard feature on most modern vehicles.) It hasbeen learned that the 02 emissions are directly related to hydrocarbonemissions which as explained is a reflection of the fuel-to-air mixture.

In the preferred embodiment, an electrical output from the 02 sensor istransmitted to the mentioned control. It is known that the desiredreading for the voltage output of the sensor as measured by the controlis, e.g., 3 volts. At startup, the reading will typically be at, e.g., 4volts, indicating a too rich mixture but desirable for startup andwarming of the engine. After a time delay to accommodate warm up, anyreading above or below, e.g., 3, will activate the control for openingand closing the valve or valves which control ambient air flow andvaporized fuel flow (more accurately an enriched mixture of air andfuel). For example, a 3.2 reading will produce an opening of the ambientair valve and/or a closing of the vaporized fuel flow. A 2.8 readingwill produce the reverse.

Whereas it would be presumed and has been assumed that an establishedfixed setting of fuel-to-air mixture would produce a stabilized mixturethroughout the operation of the engine, such has been determined to benot the case. There are many variables that need to be controlled oraccommodated. The liquid fuel temperature is known to have the greatestimpact on hydrocarbon emissions and fuel efficiency, and thattemperature will vary by small but very significant degrees oftemperature due to environmental changes, i.e., temperature, elevation,humidity, and the like. Thus, in the preferred embodiment, a quantity offuel to be vaporized is precisely temperature controlled tosubstantially eliminate the effect of such environmental variables.

Regardless, there still remain significant changes that are notcontrolled simply by maintaining the liquid fuel temperature. Theseremaining variables are accordingly accommodated by monitoring the 02sensors. To the extent that the fuel mixture strays from the desiredreading from the 02 monitor, the mixture is corrected, i.e., by changingthe setting of a valve or valves.

Whereas the above improvements are considered the primary features forthe preferred embodiment, the following is also considered to provideadditional benefit.

Again in the preferred embodiment, a quantity of liquid fuel, e.g., onegallon of fuel, is inserted into a vaporization tank. The fuel occupies,e.g., the lower half of the tank, and a heating element and temperaturesensor is provided in the fuel-containing portion of the tank. Thetemperature is set and maintained at, e.g., 74 degrees, and thattemperature causes vaporization of the fuel, the vapor rising from theliquid surface into the upper half of the tank. Within the tank, in theupper half, there is an ambient air inlet and a vaporized fuel outlet. Asequence of baffles directs air from the inlet and across the surface ofthe liquid fuel to the outlet which is connected to an outer firstconduit. The ambient air temperature is stabilized by its movement overthe liquid and in the process mixes with the rising fuel vapor. Asexpelled through the outlet and into the first conduit, such becomes thevaporized fuel heretofore alluded to and which is perhaps more correctlyidentified as an enriched fuel air mixture. A secondary source ofambient air is conducted through a second conduit and merges with thevaporized fuel of the first conduit. Prior to said joining of the airand vaporized fuel, at each or a selected one of the first and secondconduits, control valves are provided which control the flow volume fromthe respective conduits to vary the amount of ambient air and vaporizedfuel that is combined into a third conduit or continuing conduit (alsoreferred to as a mixing chamber) which in turn conveys the mixture tothe engine's intake manifold.

A further problem for which a solution had to be derived was thediscovery that the process as described, when vaporizing the commongasolines that are commercially available, generates a liquid residualthat does not readily vaporize, e.g., at the temperature settingconsidered otherwise optimal. Over a period of time, this liquidresidual becomes a greater and greater portion of the liquid content ofthe vaporization tank. Thus, a provision is made for a periodic purgingof the liquid residual from the tank.

Whereas it was determined that the residual liquid burned acceptablywell in conventional engines, and particularly to the extent that thesystems of the preferred embodiment are adaptable and applied asretrofits to such conventional engines, a first solution is thealternate running of the engine, i.e., on vaporized fuel as describedabove, and then, as desired, converting back to conventional liquid fueloperation wherein the residual liquid is used to fuel the engine. Arecycling procedure may be established to (a) fill the tank with e.g., agallon of liquid gasoline; (b) vaporizing 80% of the fuel and thenswitching to conventional engine operation to burn off the liquidresidual; and (c) refill the tank and switch back to vaporized fuel.Other solutions are certainly contemplated. The residual can be simplyextracted from the tank on a periodic basis, stored until refueling isrequired, and then disposed of or preferably transferred for use in aconventional engine use.

A further enhancement to fuel economy was discovered by incrementalincreases in the temperature settings for heating the fuel in thevaporization tank. For example, it may be found optimal to heat the fuelto a temperature of e.g. 80 degrees at the outset, but the chemicalmakeup of that fuel changes as the more active component of the fuelvaporizes. The same temperature produces less vapor and the engine willdetectably lose power. At a detected power loss it may be desirable toraise the temperature e.g. to 82 degrees which will increasevaporization and reinstate the power. Whereas theoretically the heat canbe repeatedly increased to the point where virtually all of the fuel isvaporized, it is considered a more desirable practice to stop theincremental heating at a point where the residual component can still beeffectively used as a liquid fuel. For example, the temperature can beincreased in 1 or 2-degree increments up to 100 degrees (or wheresubstantially 80% of the fuel is vaporized). At that point the processis interrupted and the vaporizing tank purged and refilled with freshfuel.

The invention will be more fully appreciated and understood by referenceto the following detailed description and drawings referred to therein.

DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic overview of a preferred embodiment of theinvention;

FIG. 2 is an operational diagram of the system utilized for theembodiment of FIG. 1;

FIG. 3 is an exploded view of the vaporization tank of FIG. 1; and

FIG. 4 is a further exploded view illustrating in particular the controlvalves of the system of FIGS. 1 and 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Reference is made to FIG. 1, which provides a schematic overview of thecomponents of a system in accordance with the present invention. Agasoline-powered engine as labeled, includes an intake port 10 connectedto the engine's throttle body. The engine, when operating, draws air andfuel through port 10. The engine includes an exhaust pipe 12 that isequipped with an 02 sensor 14. The engine, intake port 10 and 02detector 14 may be standard equipment provided for a conventionalgasoline-driven vehicle, and the remainder of the components of theillustrated embodiment are incorporated into the system to achieve theobjectives of the present invention.

Item 16 represents an air box through which ambient air is drawn whenoperating the engine. Air conducting conduits 18 and 20 from air box 16provide the desired airflow to the remainder of the system as will bedescribed.

Conduit 20 includes a valve 22 that controls the volume of air directedthrough conduit 20 and which is conveyed to a vapor producing tank 26via the tank's top or cover 24.

Conduit 18 includes a valve 28 which controls the volume of ambient airthat is directed into a mixing chamber 30.

Returning to the vapor-producing tank 26, the tank is provided with flowcontrol apparatus, e.g., baffles, which will be later explained, but forthis overview description it will be understood that air from conduit 20(as controlled by valve 22) enters the tank 26 through the top 24,liquid fuel 28 is drawn from a gas tank 32 via conduit 34, hot waterheating coils immersed in the liquid fuel via inlets and outlets 36, 38heat the gas/fuel 28 and generate vapors 40. The vapors are picked up bythe airflow from air conduit 20 and directed out through conduit 42 tothe mixing chamber 30 but controlled by valve 44. The air vapor mixtureof conduit 42 is intermixed in mixing chamber 30 with ambient air fromconduit 18, and the mixture is directed through the intake port 10 andfrom there into the combustion tank of the engine.

Reference is now also directed to FIG. 2 which illustrates an automaticcontrol process for the air, vapor, and fuel flow rates referred to inFIG. 1. Each valve 22, 28 and 44 are opened and closed as desired(between any of the unlimited positions between fully opened and fullyclosed) by motors, e.g., stepper motors 22′ 28′ and 44′.

It has been determined that fuel efficiency can be measured by thehydrocarbons that are emitted from the vehicle exhaust. Unfortunately,the elimination of hydrocarbons from gasoline-produced engines currentlyavailable cannot be total as such produces an undesired and unpermittedemission of nitrogen oxides. Thus, one first determines the level ofnitrogen oxide that is permitted and then the lowest level ofhydrocarbons that will stay within the limits permitted for therestriction on nitrogen oxide.

It has further been determined that 02 detectors for detecting a levelof 02 in the vehicle's exhaust and which have been incorporated into theexhaust system of later model vehicles, are directly related to thelevel of hydrocarbons in that same exhaust. Thus, one can determine what02 reading of the detector 14 produces the optimum fuel efficiency. Forexample, a desired hydrocarbon level may be determined to exist when the02 monitor produces a reading of 3 volts.

Returning to FIG. 1, it has been determined that fuel efficiency isachieved by controlling the ratio of fuel-to-air mixture achieved at themixing chamber 30 from which the mixture enters the engine intakethrottle body. It is known that the vapor-air-mixture directed into themixing chamber 30 from conduit 42 is too rich, e.g., 1 part fuel to 10parts air, and of course the air only from conduit 18 has zero partsfuel. The desired mixture may be that which achieves a 30 to 1 ratio,e.g., of 2 cubic feet of air, through valve 28 for each cubic foot ofair/vapor through valve 44.

Whereas the valves 28 and 44 can be set to achieve the desired mixtureat a given point in time, it has been learned that many factors affectthe ratio achieved in the vapor/fuel mixture flowing through conduit 42.

Assuming a specific hydrocarbon emission is desired, a reading of the 02detector will verify that this desired mixture has been achieved, asthat reading also indicates the hydrocarbons in the exhaust. Asexplained, a fixed setting will not likely achieve the optimum ratioover any given period of time. Any temperature change, any elevationalchange and even differences in fuel make up will skew the vapor/fuelmixture flowing from the tank 26 to the mixing chamber 30.

Accordingly, the valves 22, 28 and 44 are operated by stepper motors22′, 28′ and 44′ (illustrated in the flow chart of FIG. 2 and inexploded perspective view in FIG. 4) which stepper motors areautomatically operated by computer C. Computer C monitors the 02 andthus the hydrocarbon emissions in exhaust 12 and should those readingsindicate too high or too low hydrocarbons, the stepper motors areactivated by the computer to change the relative fluid volumes fromconduit 18 and conduit 42. Should the reading show a too highhydrocarbon level, the vapor/air flow of conduit 44 needs to belessened, e.g., the valve 44 closed, or, e.g., the valve 28 opened, or,e.g., both closing of valve 44 and opening of valve 28.

The adjustment may take place in stages, i.e., a 1° closing of valve 44,a re-reading of the 02 detector followed by repeated partial closing ofvalve 44 or alternatively the partial opening of valve 18 or acombination of both. Valve 22 can also be a factor as restricting airflow into conduit 20 will slow the flow of air to the tank 26, thus toconduit 42, while also diverting more airflow through valve 28.

The structure as described enables the designer to design a system thatwill theoretically provide the desired result in fuel-to-air mixture(e.g., 1 to 30) as deemed desirable, but then in recognition of theimpact of small environmental changes that produce substantialdeviations in efficiency, provide automatic adjustments that areresponsive to real time readouts from an exhaust monitor, e.g., an 02detector.

Reference is now made to FIG. 3, which illustrates the components of thevaporizing tank 26. The tank 26 consists of a metal box 48 havingdimensions of about 4″×8″×12″. Fitted to the bottom of the tank is a hotwater coil 50 that includes an inlet 52 and outlet 54 which, whenassembled to the box 48, extends from the box via inlet 52′ and outlet54′.

Seated onto the box bottom and over the coil 50 is a baffle grid 56. Theplates of the baffle grid 56 include slots 58 which enable the seatingof the grid over the coil 50. Baffle grid 56 includes fastener tabs 60and assembled to the fastener tabs 60 is a lower baffle plate 62 havingspaced circular opening 64. The baffle plate 62 is seated below theupper edge of box 48 (defined by flange 84) and affixed to the flange 84is an upper baffle plate 66. Extending flanges 68 of baffle plate 66protrude laterally from the box and provide the means to secure the box48 to the body of the vehicle. Upper flange 68 has rectangular openings70.

Secured to the upper baffle plate 66 and in alignment with an air inletto be described is a secondary upper baffle plate 72, reduced in sizeand secured to the upper plate 66 so as to cover a substantial portionof the opening 70′. Provided in this secondary plate is a plurality ofsmall holes, e.g., five holes 74 having a size of about a quarter inchin diameter. Baffle plate 72 provides an impediment to airflow from airinlet 78 and diverts the air flow laterally and downwardly within thetank 26.

Completing the assembly is the top or cover 24 which has a complex shapewhich can be described as a distorted pyramid shape. The apex of thepyramid shape is positioned at one end whereat an air inlet 78 isprovided A vapor air outlet 80 is provided at the same end but along theside wall of the pyramid shape. The flange 82 forming the peripheraledge of the top 24 includes bolt holes which line up with bolt holes inflange portion 76 of baffle plate 66 and with bolt holes in a flange 84forming the peripheral edge of box 48. Bolts (not shown) are insertedthrough the aligned bolt holes to fasten the components together. Afloat 86 contained in the box 48 determines the level of liquid gasolinecontained in the box. The liquid gasoline enters the box through conduit34 and a recycling conduit 90 is provided to drain and/or circulate thegasoline in the vaporizing tank 26 as may be desired.

In operation liquid gasoline is filled to a level of about ¾ inch in thebottom of the box 48 which is above the position of the heater coils 50and below the top of the baffle grid 56. The baffle grid 56 and baffleplate 62 primarily prevent sloshing of the gasoline during driving ofthe vehicle. As the liquid gasoline vaporizes (induced by the heatingcoil 50) air from inlet 78 is dispersed across the liquid surface viabaffle plates 72 and 68 which collects vapors 40 (see FIG. 1) and isthen directed through outlet 80 and to the mixing chamber 30 via conduit42 as previously discussed.

As gasoline is vaporized and drawn from the surface of the liquidgasoline, the gasoline level diminishes which is detected by the float86. As determined desirable by the system, the gasoline is replenishedthrough inlet 34. After some period of time, the gasoline starts tobecome contaminated (does not vaporize) and it is desirable to purge thetank. This can be done by converting the engine to gasoline use anddrawing the residual gas of the tank 26 through the conventional gasinjection system. It can also be simply drained into a holding tank andutilized for other power equipment, e.g., a powered law mower.

As explained in the Summary of the Invention, a further improvement isthe controlled modification to the temperature of the fuel in thevaporization tank. The temperature at the outset is established toprovide a desired vaporization of a quantity of fresh fuel, e.g. 74degrees (but note this initial desired temperature will likely changewith different fuel types and for example 80° may be just as valid astart temperature). A temperature sensor previously referred to isutilized to control the heat generated by a heating source, e.g. theindicated water heating coils immersed in the liquid fuel.

The power generated by the engine at the initial fuel temperature ismonitored and when a determined power loss is detected, the temperatureof the fuel in the vaporization tank is increased, e.g. by 1 or 2 degreeincrements. The loss of power is simply a result of the above describedvaporization process. The liquid gasoline produces more vapors initiallythan it does as time goes on. The engine requires a quantity of vapor torun correctly and that quantity of vapor exists when the gasoline isfresh but not after some time vaporizing. This loss of power is detectedby the 02 sensor that reports the air to fuel ratio. Many things such ashigh or low levels of hydrocarbons, carbon dioxide and oxygen can bederived from the 02 sensor. When there is a loss of power, thehydrocarbons and carbon dioxide levels go extremely low and the oxygenlevel goes extremely high as well as higher air to fuel ratio. Any orall of these can be utilized as a signal for loss of power.

The initial cure to the power loss is to adjust either the ambient airvalve 28 or vapor value 44 or both. As the vaporization processcontinues, the ambient air valve will close and the vapor valve willopen in response to the less and less potent liquid gasoline that isproducing the required vapor. Eventually the vapor valve will be fullyopened and the free air valve will be fully closed. At this point thetemperature of the fuel is increased. Heating the gasoline in 1 or 2degree increments is enough to increase the production to adequatelyprovide the needed fuel vapors to the engine. As the heat is increased,the vapor valve moves away from its fully opened position until the newtemperature is no longer adequate at which time the vapor valve opensand will eventually will be fully opened until more heat is added to theliquid gasoline. The process will repeat itself until a predeterminedtemperature is reached at which time the remaining liquid is drained,e.g., using the stock fuel injection system.

The formula for signaling the change from vapor to liquid fuel is asfollows: highest allowed heat of liquid gasoline plus vapor valve fullyopened plus input that the engine is no longer being provided the neededvapor to perform properly equals switch from vapor system to stock fuelinjection system and burn-off residual liquid.

The system is designed so that the residue in the tank does not becomeso contaminated that it cannot be effectively used as a liquid fuelsupply. For example, it may be determined that a power loss detectedwith the fuel in the tank heated to 100 degrees will trigger theswitch-over, i.e., purging of the tank. Other triggering mechanism maybe utilized such as monitoring the fuel volume and initiatingswitch-over, e.g. when 80% of the fuel is depleted.

Whereas the above is considered a preferred embodiment, the reader willreadily understand that numerous modifications and variations may bemade without departing from the intended scope of the invention.Accordingly, the invention is not limited to the structures as describedabove but fully encompasses the definitions of the appended claims.

1. A fuel supply assembly for a gasoline fueled engine which includes acombustion chamber for combusting fuel and an exhaust for the combustedfuel, which assembly comprises: a vaporizing tank, a quantity of liquidgasoline fuel contained in the tank, a heating source for heating theliquid gasoline fuel to promote vaporization of the fuel, and atemperature control for controlling the heating source and thereby thetemperature of the liquid fuel as contained in the tank; a conduitarrangement intermixing vaporized gasoline fuel from the tank withambient air, and for conveyance thereof to the combustion chamber of agasoline fueled engine, said conduit arrangement including controllablevalving for controlling the intermixture of said vaporized fuel andambient air; a monitor monitoring the exhaust for the combusted fuel anddetermining thereby a variation from a desired intermixture of saidvaporized fuel and ambient air, said controllable valving responsive tosaid monitor for altering the intermixture of said vaporized gasolinefuel and said ambient air to achieve the desired intermixture; and anengine power sensor for sensing engine power loss when receiving thedesired intermixture and inducing a higher temperature of said liquidfuel in said tank to offset said power loss.
 2. A fuel supply assemblyas defined in claim 1, including a system design that determinesdepletion of the fuel to a pre-established residual level and initiatingtermination of the vaporization at said level.
 3. A fuel supply assemblyas defined in claim 2 wherein'said depletion is determined by a maximumtemperature of said liquid fuel, said system design responsive to saidmaximum temperature for initiating termination.
 4. A fuel supplyassembly as defined in claim 2 wherein said depletion is determined by aminimum liquid fuel level in said vaporizing tank and said system designresponsive to said minimum liquid fuel level for initiating termination.